We pick h.root-servers.net, one of the 13 root servers (1), and ask it about mail.yahoo.com.vn and learn that vn is delegated to seven name servers (2), so we ask b.dns-servers.vn where we learn that yahoo.com.vn is delegated to two name servers, including ns1.yahoo.com (3), so we ask that one where we see a CNAME from mail.yahoo.com.vn to rc.yahoo.com, so we have to start all over again. We pick i.root-servers.net, one of the 13 root servers (4), and ask it about rc.yahoo.com and learn that com is delegated to 13 name servers (5), so we ask m.gtld-servers.net where we learn that yahoo.com is delegated to five name servers, including ns3.yahoo.com (6), so we ask that one and see a second CNAME from rc.yahoo.com to rc.g01.yahoodns.net. We start over for the third time and we pick g.root-servers.net, one of the 13 root servers (7), and ask it about rc.g01.yahoodns.net and learn that net is delegated to 13 name servers (8), so we ask e.gtld-servers.net where we learn that yahoodns.net is delegated to five name servers, including ns1.yahoo.com (9), so we ask that one and learn that g01.yahoodns.net is delegated to eight name servers (10), so we ask yf8.yahoo.com and see yet another CNAME from rc.g01.yahoodns.net to any-rc.a01.yahoodns.net. We have yet again to start all over and we already know that ns3.yahoo.com is authoritative for yahoodns.net (11) and ask it about any-rc.a01.yahoodns.net and learn that a01.yahoodns.net is delegated to two name servers (12), so we ask yf1.yahoo.com and get the following answer:
Mail.yahoo.com.vn is hosted on five servers in Sunnyvale, CA, United States even though the hostname implies Vietnam.
The two IP numbers 68.180.206.184 and 98.139.102.145 together
There are several thousand of host names that point to the two IP numbers 68.180.206.184 and 98.139.102.145 together, hereafter referred to as "IP group 1".
